1. Field of the Invention
This invention generally relates to a bicycle crank assembly. More specifically, the present invention relates to a composite bicycle crank assembly.
2. Background Information
A bicycle crank arm is a component for connecting a pedal to a crank axle, and for transmitting a pedal force from the pedal to a chain. The crank arm should have high strength in order to prevent damage or deformation despite the crank arm being repeatedly subjected to loads from the pedal, and high rigidity in order to prevent deformation or flexing when the pedal is depressed. The crank arm is preferably also designed to be as lightweight as possible in order to reduce the weight of the entire bicycle. In the past, many front crank sets often used solid crank arms that were forged metal members. These solid crank arms can be quite heavy depending on the material. In more recent years, these solid crank arms have been made from lighter weight metal alloys and/or have been constructed as hollow areas and/or recesses in order to reduce weight (e.g., see, U.S. Pat. No. 6,058,803 and U.S. Pat. No. 6,145,184). In addition, more recently, crank arms have been made with one or more portions made of a hard plastic material or a fiber reinforced resin material in order to reduce weight (e.g., see, U.S. Pat. No. 7,527,277).